Saying goodbye to rye, wheat, and barley is big business. Gluten-free products line the aisles of most grocery stores, and specialty bakeries are increasingly catering to the grain-restricted diets of a growing number health conscious Canadians.

Now a large-scale study by Harvard University is casting serious doubt on the health benefits of gluten-free diets for people without celiac disease.

A team led by Dr. Andrew Chan, an associate professor of medicine at Harvard, used diet and health outcome data collected from 110,000 health professionals over 26 years to create estimates of gluten in the diet.

The findings contradict the broad-stroke vilification of gluten that has become popular among many non-celiacs.

“There really is no evidence to suggest that gluten in someone who doesn’t have a gluten allergy has any long-term health effects,” he told CTV News on Wednesday. “We found that those individuals in our study who ate the highest level of gluten actually had a lower risk of developing heart disease compared to those that ate the lowest amount of gluten.”

He says that’s because high gluten intake was found to have a direct correlation with the amount of whole grains in the diet. Whole grains are associated with a wide range of health benefits, including lowering the risk of heart disease and cancer.

“People who eat whole grains have a better response … in terms of how they handle blood sugar. It also tends to keep the pounds off,” Dr. Chan said. “If you don’t have an allergy to gluten, and you are restricting you diet because you think it’s going to help you in the long run, reconsider that.”

He stresses that a gluten-free diet is vitally important for those living with celiac disease.

The inherited autoimmune disorder where the body reacts to the proteins in grains causing abdominal pain and anemia impacts about one per cent of Canada’s population, or about 350,000 people, according to Health Canada. Eating gluten has been found to increase the risk of coronary heart disease for those individuals.

Betsy Heibert is one of them. She started a bake shop to cater to her fellow celiacs. As the gluten-free movement grew, so did her business. She believes there are many people who are undiagnosed who find changing their eating can change their lives.

“If you find you have more energy, and it is making a genuine impact on your body, keep eating it, keep eating gluten free,” she said.

Celiac expert Shelly Case warns those who make snap dietary decisions without a medical diagnosis may be needlessly missing out on vital nutrients.

“It is not a magic bullet for everything that ails a person. The only people that need to follow a strict gluten-free diet for life are those with celiac disease,” she said.

The gluten-free movement punches far above the weight of those with celiac disease.

Agriculture and Agri-Food Canada estimates 10 million Canadians -- about one third of the population -- look for gluten-free labels on store shelves. The vast majority, more than seven million, perceive gluten-free products to be a healthier choice, or in some cases have a family member with a medical need.

“There has been a notion that gluten is harmful that has been pushed by the food industry and popular diet books and word of mouth,” said Dr. Chan.

That perception adds up at the grocery check-out. A 2013 comparison study by Halifax gastroenterologist Dr. Mohsin Rashid found on average that gluten-free foods are 162 per cent more expensive than their corresponding non-gluten free product. That price gap is so significant that the Canada Revenue agency lists gluten-free food products as an eligible medical expense.

“We know gluten free foods are more expensive,” Dr. Chan said. “People have started to assume that this is the way to go in terms of optimizing your health. There really has not been that level of scientific data to support that movement.”

With a report from CTV’s Jill Macyshon in Winnipeg